Use standard exceptions in client._get_leader_for_partition()

- drop custom PartitionUnavailable exception
- raise UnknownTopicOrPartitionError or LeaderNotAvailableError
- add tests for exception raises

1 files changed, 28 insertions, 15 deletions

diff --git a/kafka/client.py b/kafka/client.py
index 4d79b41..38136af 100644
--- a/kafka/client.py
+++ b/kafka/client.py
@@ -8,9 +8,9 @@ import kafka.common
 
 from kafka.common import (TopicAndPartition, BrokerMetadata,
                           ConnectionError, FailedPayloadsError,
-                          PartitionUnavailableError, LeaderNotAvailableError,
-                          KafkaUnavailableError, KafkaTimeoutError,
-                          UnknownTopicOrPartitionError, NotLeaderForPartitionError)
+                          KafkaTimeoutError, KafkaUnavailableError,
+                          LeaderNotAvailableError, UnknownTopicOrPartitionError,
+                          NotLeaderForPartitionError)
 
 from kafka.conn import collect_hosts, KafkaConnection, DEFAULT_SOCKET_TIMEOUT_SECONDS
 from kafka.protocol import KafkaProtocol
@@ -63,20 +63,37 @@ class KafkaClient(object):
         Returns the leader for a partition or None if the partition exists
         but has no leader.
 
-        PartitionUnavailableError will be raised if the topic or partition
+        UnknownTopicOrPartitionError will be raised if the topic or partition
         is not part of the metadata.
+
+        LeaderNotAvailableError is raised if server has metadata, but there is
+        no current leader
         """
 
         key = TopicAndPartition(topic, partition)
-        # reload metadata whether the partition is not available
-        # or has no leader (broker is None)
-        if self.topics_to_brokers.get(key) is None:
-            self.load_metadata_for_topics(topic)
 
-        if key not in self.topics_to_brokers:
-            raise PartitionUnavailableError("%s not available" % str(key))
+        # Use cached metadata if it is there
+        if self.topics_to_brokers.get(key) is not None:
+            return self.topics_to_brokers[key]
+
+        # Otherwise refresh metadata
+
+        # If topic does not already exist, this will raise
+        # UnknownTopicOrPartitionError if not auto-creating
+        # LeaderNotAvailableError otherwise until partitions are created
+        self.load_metadata_for_topics(topic)
+
+        # If the partition doesn't actually exist, raise
+        if partition not in self.topic_partitions[topic]:
+            raise UnknownTopicOrPartitionError(key)
+
+        # If there's no leader for the partition, raise
+        meta = self.topic_partitions[topic][partition]
+        if meta.leader == -1:
+            raise LeaderNotAvailableError(meta)
 
-        return self.topics_to_brokers[key]
+        # Otherwise return the BrokerMetadata
+        return self.brokers[meta.leader]
 
     def _next_id(self):
         """
@@ -136,10 +153,6 @@ class KafkaClient(object):
         for payload in payloads:
             leader = self._get_leader_for_partition(payload.topic,
                                                     payload.partition)
-            if leader is None:
-                raise LeaderNotAvailableError(
-                    "Leader not available for topic %s partition %s" %
-                    (payload.topic, payload.partition))
 
             payloads_by_broker[leader].append(payload)
             original_keys.append((payload.topic, payload.partition))